You will have to buy as many different brands and projectile weights as you can afford and shoot them to find out. Weapons, like people, exhibit preferences.
There are varying opinions on what ammo is the "best." Generally speaking, the best ammo to use is whichever ammo is the most reliable in your particular gun.
Federal premium ammo
300 USD or so
No
Not enough sales
The ammuntion it is chamberd for.
Idaho potatoes
The Remington 700 CDL "Boone and Crockett" edition sports a 26" barrel.
I have had good success with Federal rifle ammo.
Gold Dot
Typically the best ammo for your Windicator is what shoots best in it.There are many different brands and weight of ammo available for you to try.I find that most every firearm likes one or two loads the best.It will be up to you to find out.If you do reload centerfire ammo then it is really enjoyable to try different weight bullets and powder combinations to bring out the best of your firearm in terms of accuracy and velocity.
Best would depend on intended use. Federal makes good 30-06 ammo. Soft point for hunting, FMJ for target use.